attribute vec3 vPosition;//顶点坐标
uniform mat4 uMVPMatrix;// 总变换矩阵
attribute vec4 aColor;//顶点颜色
varying vec4 vColor;//片元
void main(){
    gl_Position = uMVPMatrix * vec4(vPosition, 1);
    vColor = aColor;//传给片元着色器
}
